Why are they there?

Tool time Tuesday and today it’s more of a device than a tool, although a lot of tools have these.  Did you ever notice the holes on the flat prongs of an electrical plug?  Why are they there?  According to How Stuff Works dot com they sever a couple functions.  First, inside the outlet there are bumps on the contact sliders that slip into those holes to help hold the plug in the outlet.  Second, the plug can be “factory sealed” by using those holes to attach a warning label or instructions that must be removed before the device can be plugged in.  Third, and less important, is the slight savings on raw material to make the plug.  Those holes are tiny, but every little bit adds up when you’re making billions of plugs every year.  One other plug fact.  The wider blade of the plug connects to the neutral side of the outlet while the thinner blade slides into the hot side.  The big round pin on the plug is the ground which protects the device in the event of a short circuit. Listen to the podcast here; https://theriver953.com/lonnies-fun-fact/